This invention relates to a method for data transfer via a radio telephone network between a Local Area Network (LAN) and a Mobile Station. The invention also relates to a data interface unit that applies the method.
A known data transfer device is connected both to a LAN and a telephone network for facilitating data transfer between these two networks. Accordingly, the data transfer device incorporates a modem by means of which data traffic coming from the LAN and transmitted to a telephone network is coded into a form that is suitable for the network. Conversely, data coming from the telephone network is converted into a form suitable for the LAN by the modem. The telephone network can be a conventional Public Switched Telephone Network (PSTN) or a radio telephone network. The Mobile Station MS, which is located at a given distance from the LAN, incorporates a modem card or a corresponding separate modem device that enables it to make use of the telephone network to set up a connection from the Mobile Station to the LAN and thereby to carry out bidirectional data transfer.
A more detailed description of a conventional method of transferring data between a Mobile Station and a LAN is shown schematically and graphically in FIG. 1. LAN 1 is connected by means of date transfer device 2 to a Public Switched Telephone Network (PSTN) 5. Data transfer device 2 incorporates a LAN-controller 3, by means of which data transfer device 2 is interfaced to LAN 1, and a modem 4, which in turn serves to interface data transfer device 2 to the PSTN 5. PSTN 5, for its part, is connected to radio telephone network 6, ie, to its Mobile Services Centre (MSC) 7 and further on to its base station 8. A bidirectional connection with mobile phone 10 is established through the intermediary of bate station 8 and via radio path 9 and by moans of these intermediaries and modem 11 with Mobile Station 12.
According to a first aspect of the present invention there is provided a method of data transfer for a radio telephone network, comprising extracting data from a data packet, assembling said data into a data structure for a radio telephone network, and transmitting the data structure to a Mobile station; and in a second aspect there is provided a method of data transfer for a radio telephone network, comprising receiving a date structure from a radio telephone network, extracting data from the data structure, and assembling said data into a data packet.
According to a third aspect of the present invention there is provided a data interface unit for data transfer for a radio telephone network, comprising a data interface unit having a data adapter for assembling data from data packets into data frames for a radio telephone system, and, correspondingly, for forming data packets from data frames for extracting data transferred from the radio telephone network.
An advantage of embodiments in accordance with the present invention is that a new method of data transfer between a LAN and a Mobile Station via a radio telephone network has been enabled.
Another advantage is that a new data interface unit for data transfer between a LAN and a Mobile Station via a radio telephone network can be developed.
The invention confers the benefit that the structure of the equipment necessary for date transfer is simpler then the structure of known data transfer equipment. Previously known data transfer equipment generally makes use of modem devices which are subject to type-approval by a competent authority before they can be used. The date interface unit according to the invention must be type-approved only in the radio telephone network in connection with which it is meant to be used. In the method according to the invention or in the data interface unit embodying it, a modem is not used but instead the data is transferred directly via a digital radio telephone network from a Mobile Station to a LAN and vice versa. In this case a fixed telephone network (PSTN) is thus not used and therefore the modem mentioned is not needed. Further, an advantage of the invention is that it makes possible a pan-European mobile telephone system employing a standardized manufacturer-independent digital radio telephone network such as GSM for data transfer between Mobile Stations and LANs. A further advantage of the invention is that via an external radio path a Mobile Station that is in contact with a LAN is apparently direct connected to the LAN by means of a LAN-controller. In addition, it to an advantage that a Mobile Station makes direct use of the operating system and data communications protocol which are needed in dealings with the LAN. Another advantage of the invention is that interfacing of the radio telephone network and a Mobile Station of the LAN is implemented in a data interface unit which in its preferred embodiment is arranged to employ a standard PCMCIA (Personal Computer Memory Card International Association) card.
In a preferred embodiment data packets of a digital packet-switched LAN are formed and stripped in a LAN-controller connected to a LAN; the data which is extracted from the data packets of the LAN is packed into date communications date packets in accordance with a data communications protocol that is known per se when the data is transferred between the LAN-controller and the Mobile Station; the data packets in accordance with the date communications protocol are inserted into data frames of the radio telephone network when the data is transferred between the LAN and a Mobile Station via a digital radio telephone network. The data frames of the radio telephone network can be existing data frames of a time-divided digital radio telephone network or they can be formed appropriately in a predetermined manner.